Module params 

Typed action parameters: what an invocation must carry, and the strict bind that checks it before anything runs.

An ActionSpec used to describe its argument in prose — "Value 0–1", "Rate, e.g. 0.5 / 1 / 2", "grayscale / sepia / invert" — and hand the raw string to a closure that parsed it leniently. A typo became a silent default. That is tolerable when a human is looking at a prompt and can see the result; it is not tolerable for a caller with no screen, whose only description of the surface is the enumeration it was handed.

So a parameter is declared, not narrated: a name, a ParamType, whether it is required, optional choices, and a description that explains meaning rather than syntax. ActionArgs::bind then refuses a missing, unknown, wrong-typed or out-of-choice argument up front, so a bad call is a refusal and never a half-applied edit.

One vocabulary, both sides

This is deliberately the same vocabulary the compositor’s headless action API already speaks (ParamType / ActionParam / ArgValue / strict ActionArgs::bind), lifted here so the app-side action model and the shell-side one share a single definition instead of converging by accident. The const constructors keep const PARAMS: &[ActionParam] = &[…] compiling verbatim; the owned constructors are what an app needs, because an app builds its parameters at runtime out of document state.

Structs

ActionArgs

Arguments for one invocation, already checked against the action’s declared parameters.

ActionParam

One typed parameter an action declares.

MadeFrom

The resource an invocation is made from: its address, as the caller names it, and the type it points at.

Enums

ArgError

Why a set of arguments does not satisfy an action’s parameters.

ArgValue

One bound argument value.

ArgViolation

How a value broke its parameter’s declared range, as data: what a failure’s details carry beside its message, so a caller corrects the call without reading the prose.

ParamType

The type of one action parameter. Deliberately small: these are values a caller with no screen can produce from a descriptor alone.

Pick

What a parameter’s value names in the workspace, so a person picks it from what is there instead of typing its encoding (PICK_ANNOTATION).

Constants

ARGUMENTS_JSON_PREFIX

Marks the legacy single-string invocation slot as carrying a canonical JSON argument object. The record-separator prefix cannot be produced by a normal palette text field, preserving unambiguous backward compatibility.

CHOICE_LABELS_ANNOTATION

Schema annotation saying how each of a parameter’s choices reads to a person: an object from choice to label; see ActionParam::with_labelled_choices. An identity is chosen by its name, never by its fingerprint.

CONTENT_ANNOTATION

Schema annotation marking a text parameter as the address of content another action produced (a content hash), not words a caller can say; see ActionParam::as_content.

FROM_ARGUMENT

The argument key a caller names the resource it makes the invocation from with: what the resources the action makes were made from (created(r)?.from, linked(r)). It is no parameter of any action, and every builder may read it, the ones that record provenance and the ones that ignore it alike.

PEOPLE_ANNOTATION

Schema annotation naming which of a parameter’s choices are people (identities, collaborators): a surface shows each with its avatar; see ActionParam::choosing_people.

PICK_ANNOTATION

Schema annotation naming what a parameter’s value picks from the workspace; see ActionParam::picking. An annotation, not an assertion: binding takes any value of the parameter’s type.

PLACE_ANNOTATION

Schema annotation marking a parameter as a place inside the resource the action is on (an item, a caret in it, a range of it); see ActionParam::as_place.

RESOURCE_KIND_ANNOTATION

Schema annotation naming the kind of resource a ParamType::Resource parameter takes; see ActionParam::of_resource_kind. An annotation, not an assertion: binding does not check it.

Functions

picked_resource_schema

The schema of a parameter that picks an existing resource of kind kind (Pick::Resource): a reference (resource_reference_schema), annotated with what it picks.

place_schema

The schema of a place inside a resource (ActionParam::as_place).

resource_reference_schema

The schema of a reference to an existing resource of the workspace, as a parameter that picks one takes it (Pick::Resource): the app that keeps it, the record it keeps it in when not its record of the workspace, its kind, its id in that app and how it reads. The label is presentation only; the app, kind and id are the address.

validate_json_schema

Validate one JSON value against the deterministic JSON Schema subset used by Tilo action contracts.

Type Aliases

Str

A string that is either a &'static str (so a parameter list can be a const) or owned (so an app can build one per frame from its document).